The present invention relates to a warp let-off motion for a loom of a type in which warp threads are delivered from two warp beams.
U.S. Pat. No. 4,262,706 shows a loom having two warp beams, in which a tension roller common to both warp beams is supported at both ends by left and right bearing means in such a manner that each end of the tension roller is movable in accordance with a variation of a load exerted on the support at the end of the tension roller by the warp tension. The rotational speed of each warp beam is controlled individually as a function of each end position of the tension roller.
If, for example, the warp tension of the left warp beam increases in this loom, the load acting on the left end support of the tension roller increases, so that the left end of the tension roller is moved and the rotational speed of the left warp beam is changed in accordance with the displacement of the left end of the tension roller. In this case, however, the increase of the warp tension of the left warp beam also increases the load acting on the right support of the tension roller more or less. Therefore, the right end of the tension roller is also moved, and the rotational speed of the right warp beam is changed while the warp tension of the right warp remains unchanged. Thus, the warp tension is varied uselessly in the right warp beam.